In recent years, a recording and playback device is here to stay: the recording and playback device is an information processing device that records and plays back content data, such as music data, on a hard disk which is storage media.
Some of the recording and playback devices rip music data from a music CD (Compact disk) and records the music data on its hard disk. Others download music data from an external music data delivery server through a network and records the music data on its hard disk (see Patent Document 1, for example).
Patent Document 1: Japanese Patent Publication No. 2000-306332.
By the way, the above recording and playback device uses the hard disk for storage media. That allows the recording and playback device to store hundreds or thousands of pieces of music data in line with its capacity.
In this manner, the recording and playback device uses the hard disk. Therefore, a user does not have to replace storage media many times while he/she has to do so with the music CDs. That improves the usability.
However, on the other hand, the recording and playback device is capable of storing hundreds or thousands of pieces of music data on the hard disk. Therefore, a user has difficulty in remembering all the music data stored in the hard disk.
Accordingly, for example, a user may not be able to remember which music data he/she has already got (or recorded on the hard disk) when he/she tries to download music data through a music data delivery page on the Internet.